Magnesium hydroxide as a green material is widely applied to aspects of fireproof materials, agriculture, and environmental protection. Five kinds of ways for obtaining the magnesium hydroxide industrially are present generally: 1. the magnesium hydroxide is produced by reacting limestone with brine; 2. the magnesium hydroxide is prepared by reacting sodium hydroxide with brine and enriched bittern cakes; 3. the magnesium hydroxide is produced by reacting calcined magnesite and dolomite with brine and enriched bittern cakes; 4. the magnesium hydroxide is prepared by reacting ammonium hydroxide with brine and enriched bittern cakes; and 5. the magnesium hydroxide is generated by using hydration of magnesium oxide, wherein the magnesium oxide here must be a light-calcined product so as to ensure the hydration activity. The way of hydrating the light-calcined magnesium oxide is most commonly used to obtain the magnesium hydroxide, the hydration is finished generally under a stirring condition, and the basic conditions of hydration are as follows: the hydration temperature is 30-60° C., the concentration of the magnesium oxide slurry is 5-20% (w/w), the hydration time is 1-24 h, and the hydration ratio is 60-80%.
From the above, the problems in the technical field of preparing magnesium hydroxide by hydration of magnesium oxide are as follows: owing to longer retention time, all the traditional ways of preparing magnesium hydroxide by hydration of magnesium oxide are of an intermittent type process, the reaction vessel is relatively large in size, the hydration efficiency is not high, and the hydration ratio is relatively low.